scholarly journals Structural Behavior of Ultrahigh-Performance Fiber-Reinforced Concrete Thin-Walled Arch Subjected to Asymmetric Load

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Jun Yang ◽  
Jianting Zhou ◽  
Zongshan Wang ◽  
Yingxin Zhou ◽  
Hong Zhang
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Load Capacity ◽  
Limit Equilibrium ◽  
Analytical Formula ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Section Design ◽  
Thin Walled ◽  
Asymmetric Load

Ultrahigh-performance fiber-reinforced concrete (UHPFRC) is an innovative material in the field of bridge engineering. With superior mechanical characteristics, this new material reduced the structural self-weight and extended the span of modern bridges. A series of tests should be conducted to establish reliable design rules for UHPFRC structures. This paper aimed at determining the compressive behavior of UHPFRC for thin-walled arch section design and a comparison was made with a normal concrete (NC) arch. Eighteen axial compression columns for arch section design and arches under asymmetric load were tested in this paper. Behaviors of the arches were assessed using various mechanical properties, including the failure pattern, load-deflection relationship, strain analysis, and analytical investigation. A finite element model (FEM) considering the material and geometric nonlinearity was developed to predict the behavior of the UHPFRC arch. Results indicated that a wall thickness of 50 mm with stirrups effectively restrained instability failure of the thin-walled compression columns. The cracking load and the ultimate load of the UHPFRC arch increased by 60% and 34%, respectively, when comparing with the NC arch. It showed the UHPFRC arch had higher load capacity and outstanding durability. The failure mode of the UHPFRC arch was similar to that of the NC arch, which belonging to the destruction of multihinges. However, the appearance of the plastic hinges was delayed, and a better elastic-plastic performance was obtained when using UHPFRC. The analytical formula for calculating the ultimate load of the UHPFRC arch was derived with high precision by using the limit equilibrium method. The results of the FEM showed good agreement with test results, and they were able to predict the behavior of the UHPFRC arches.

Behavior of High Strength Hybrid Reinforcement Concrete Beams

2020 ◽  
Vol 12 (7) ◽  
Author(s):  
Khanda Ali Al-Billbassi ◽  
◽  
Mushriq Fuad Kadhim Al-Shamaa ◽  
Keyword(s):  
Residual Strength ◽  
Ultimate Load ◽  
Steel Fiber ◽  
Load Capacity ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Ultimate Load Capacity ◽  
Cross Sectional ◽  
Sectional Shape

Six proposed simply supported high strength-steel fiber reinforced concrete (HS-SFRC) beams reinforced with FRP (fiber reinforced polymer) rebars were numerically tested by finite element method using ABAQUS software to investigate their behavior under the flexural failure. The beams were divided into two groups depending on their cross sectional shape. Group A consisted of four trapezoidal beams with dimensions of (height 200 mm, top width 250 mm, and bottom width 125 mm), while group B consisted of two rectangular beams with dimensions of (125 ×200) mm. All specimens have same total length of 1500 mm, and they were also considered to be made of same high strength concrete designed material with 1% volume fraction of steel fiber. Different types and ratios of FRP rebar were used to reinforce these test beams. The study’s principle variables were the amount and type of flexural reinforcement (glass FRP and basalt FRP) and beam cross-sectional shape (rectangular and trapezoidal). The load-deflection behavior and ultimate load capacity of the beams were studied and compared with one another under flexural test with symmetrical two-point loading. The results show that increasing the reinforcement ratio resulted in higher post cracking flexural stiffness, and higher residual strength, as well as caused an increase in the first cracking load and ultimate load capacity ranged from 3 to 16.9%, and 4.6 to 7.3% respectively. When the GFRP rebars replaced by BFRP, the overall beams flexural performance showed outstanding improvements. Moreover the results indicate that increasing the top width of the beam cross section led to a significant enhancement in the first crack load ranged from 16 to 32.4%, also a remarkable increases in the ultimate load capacity in the range of 35.5 to 35.8% were indicated in the trapezoidal beams compared to rectangular beams. However the results show that the deflections were similar and were approximately 1.07–1.54 mm for all test beams. It is worth noting that the general flexural behavior of all the test beams indicated a ductile behavior with a gradual reduction in strength and high residual strength pre to failure due to proposing steel fiber presence.

scholarly journals Flexural Behavior of Composite Concrete Slabs Made with Steel and Polypropylene Fibers Reinforced Concrete in the Compression Zone

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3616 ◽  
Author(s):  
Barbara Sadowska-Buraczewska ◽  
Małgorzata Szafraniec ◽  
Danuta Barnat-Hunek ◽  
Grzegorz Łagód
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Load Capacity ◽  
Fiber Reinforced Concrete ◽  
Concrete Slabs ◽  
Polypropylene Fibers ◽  
Compression Zone ◽  
Fiber Reinforced ◽  
Reinforced Concrete Slabs ◽  
Fiber Concrete

The paper presented aimed at examining the effect of a fiber-reinforced concrete layer in the compressed zone on the mechanical properties of composite fiber-reinforced concrete slabs. Steel fibers (SF) and polypropylene fibers (PP) in the amount of 1% in relation to the weight of the concrete mix were used as reinforcement fibers. The mixture compositions were developed for the reference concrete, steel fiber concrete and polypropylene fiber concrete. The mechanical properties of the concrete obtained from the designed mixes such as compressive strength, bending strength, modulus of elasticity and frost resistance were tested. The main research elements, i.e., slabs with a reinforced compression zone in the form of a 30 mm layer of concrete with PP or SF were made and tested. The results obtained were compared with a plate made without a strengthening layer. The bending resistance, load capacity and deflection tests were performed on the slabs. A scheme of crack development during the test and a numerical model for the slab element were also devised. The study showed that the composite slabs with fiber-reinforced concrete with PP in the upper layer achieved 12% higher load capacity, with respect to the reference slabs.

scholarly journals Flexural Behavior of Ultra-High Performance Fiber Reinforced Concrete Scale Tunnel Segment

2018 ◽  
Vol 38 ◽  
pp. 03037
Author(s):  
Kun Ni ◽  
Fa Sheng Zhang ◽  
Yun Xing Shi ◽  
Yan Gang Zhang ◽  
Jing Bin Shi
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Ultimate Load ◽  
Fiber Reinforced Concrete ◽  
Flexural Behavior ◽  
Fiber Reinforced ◽  
Flexural Performance ◽  
Four Point Bending ◽  
High Performance Fiber ◽  
Elastic Stage

To reduce the weight of precast tunnel segment, ultra-high performance fiber reinforced concrete (UHPFRC) was studied to cast the segment. The flexural performance of UHPFRC scale tunnel segments were tested in this work. The weight of the UHPFRC thinner scale tunnel segment was only 80% of reinforced concrete (RC) segment. The segments were loaded as per CJJ/T 164-2011, and the four-point bending system was used. The results showed that the cracking load increased 50%, and 0.2 mm crack width load increased 22%, and the yield load increased 11%, and the ultimate load only decreased 1%. The stiffness of elastic stage of UHPFRC segment looked the same compared to RC segment. In a word, the UHPFRC thinner segments showed excellent flexural performance beyond the traditional RC segment.

THE FRACTURE TOUGHNESS OF THIN-WALLED COVER SHELLS HYPERBOLIC PARABOLOID SHAPED OF FERROCEMENT AND STEEL FIBER CONCRETE UNDER THE ACTION OF OPERATING LOADS

2020 ◽  
pp. 89-96
Author(s):  
О V Andriichuk ◽  
S O Uzhehov
Keyword(s):  
Fracture Toughness ◽  
Reinforced Concrete ◽  
Negative Curvature ◽  
Steel Fiber ◽  
Fiber Reinforced Concrete ◽  
Thin Shells ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete ◽  
Hyperbolic Paraboloid ◽  
Thin Walled

Experimental research of new materials and structures with improved parameters of strength, fracture toughness, bearing capacity and their lifetime in comparison with typical elements is an actual problem of building science.Nowadays there is a trend to design and use for buildings covering the new design solutions as the thin shells. One of the types of thin shells are Gaussian shells with negative curvature. It’s worth to note that in the last decade, a considerable number of researches of thin-walled structures made of steel fiber reinforced concrete were conducted, which confirmed the efficiency of its use to enhance their hardness, fracture toughness and thus longer life.The article presents the results of the authors’ experimental studies of fracture toughness of thin-walled cover structures with Gaussian negative curvature in the shape of hyperbolic paraboloid made of ferrocement and steel fiber reinforced concrete under the action of the operating load.The load application was carried out for ten steps, after each step the pause was for 15...20 min, during which the data of the strain-gauge station VNP-8 was recorded, using a microscope were measured and recorded the width of the cracks, deflections of the structure were measured etc.The external force was evenly-distributed to its applications and the impact was simulated according to the real conditions of construction use.The experimental part of the research was conducted at the laboratory of building materials and structures of Lutsk National Technical University. In scientific work carried out mapping and comparison of the obtained experimental results, carried out processing and analysis, presents the conclusions.During the researches it was found that the fracture toughness of thin-walled shell cover with Gaussian negative curvature in the shape of a hyperbolic paraboloid with dispersed reinforcement (steel fiber reinforced concrete) is higher than in the shell made of ferrocement. Accordingly, it can be argued about the increasing of the lifetime of steel fiber reinforced concrete shell covering in comparison with the ferrocement shell.

Sign in / Sign up

Export Citation Format

Share Document